With the continuous development of society and economy, people's standard of living is improving increasingly, accompanied with higher requirements on products. Wired doorbells cannot fully meet the consumers' increasingly diverse demands any more. It is a trend and direction to get rid of the constraints of wired doorbells and realize wireless communication doorbells with intercom function. Wireless visual doorbells currently available on the market can realize two-way communication in both video and voice, with the need of being connected over a wireless network such as 2.4 G, 1.8 G, 900 MHz or WiFi. Restricted to a series of problems such as signal strength, transmission distance, network requirements and cost, the wireless visual doorbells have been unable to quickly occupy the market. Although some of wired and wireless doorbells can realize indoor and outdoor communication, the communication with an indoor person can be realized only after an outdoor person keep presses the key. However, many visitors have no idea of this or the communication distance is short or the Installation is very complex.
With the development of the walkie talkie communication, the walkie talkie market gradually becomes an important professional communication market, and walkie talkie are one of the fastest growing communication products in addition to mobile phones. walkie talkie have been widely applied in various aspects of the national economy, and have become important wireless communication devices for family life, traffic management, petrochemical engineering, building construction, property security and other departments. Due to the rapid development of the walkie talkie technology, the cost becomes lower, and applications which could never be expected in many conventional fields have become feasible. The introduction of the intercom technology will greatly improve people's quality of life: (1) many wired products may be turned into wireless products, so the installation cost is reduced and the purpose of mobile and convenient use is realized; (2) the communication is realized by the products' own receiving and transmitting functions without any other networks; (3) with built-in batteries, the walkie talkie can still operate normally even in the event of power failure; and (4) the walkie talkie technology has a long transmission distance, which is an advantage which cannot be matched by the 2.4 G, 900 MHz, WiFi and other technologies.